1. Field of the Invention
The present invention relates to a lock, and more particularly to a demolishment-proof lock. The lock has a first steel plate and a second steel plate securely attached to the bottom of the lock, wherein the first steel plate has a first through hole and the second steel plate has a second through hole corresponding to and communicating with the first through hole. The second through hole has a diameter smaller than that of the first through hole so that a circular cap received in the first through hole is kept in the first through hole and between the first and second steel plates to prevent the core of the lock from being forcefully pulled out.
2. Description of Related Art
A conventional lock (5) as shown in FIG. 5 has rivets (51) protruding out from a bottom of the lock body (not numbered) and an exposed core (52). With this kind of structure, an unauthorized person may destroy the lock by damaging the rivets (51) or by forcefully pulling the core (52) out of the lock (5).
In order to obviate the opportunity for the unauthorized person to destroy the lock, an improved lock (6), as shown in FIG. 6, is invented. The lock (6) has a protection plate (61) securely attached to the bottom of the lock (6) and has a centrally-defined through hole (63) to correspond to the core (62) and bores (64) defined in a peripheral end face of the steel plate (61) to correspond to the rivets (60). With such an arrangement, the rivets (60) are concealed in the steel plate (61) so that deliberately damaging the rivets (60) is prevented. However, people still have access to the core (62), and consequently, the lock (60) may still be forced open.
To overcome the shortcomings, the present invention tends to provide an improved lock structure to mitigate and obviate the aforementioned problems.
The primary objective of the present invention is to provide an improved lock for prevention of destruction of the lock.
In order to accomplish the objective, the lock has a first steel plate and a second steel plate respectively and securely attached to the bottom of the lock. The first steel plate has a first through hole and the second steel plate has a second through hole corresponding to and communicating with the first through hole. The second through hole has a diameter smaller than that of the first through hole so that a circular cap received in the first through hole and having a slit defined to correspond to the keyhole of the core is kept in the first through hole and between the first and second steel plates to prevent the core of the lock from being forcibly removed.
Other objects, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.